How Laser Cutting Works
A focused laser beam (fiber or CO₂) melts, burns, or vaporizes material along a programmed path. An assist gas (nitrogen, oxygen, or air) blows the molten material out of the cut. The result: clean edges, tight tolerances, and minimal heat-affected zone.
Fiber vs CO₂ Lasers
| Factor | Fiber Laser | CO₂ Laser |
|---|---|---|
| Wavelength | 1.06 μm | 10.6 μm |
| Best for | Metals (especially thin) | Thick steel, non-metals |
| Speed (thin metal) | 2–5× faster | Baseline |
| Reflective metals | Handles well | Struggles (brass, copper, aluminum) |
| Operating cost | Lower (electrical efficiency) | Higher (gas consumption) |
| Edge quality (thick steel) | Good | Excellent |
Fiber lasers are taking over the industry. Most modern shops run fiber for sheet metal work.
Capabilities
| Material | Max Thickness (fiber) | Typical Tolerance |
|---|---|---|
| Mild Steel | 1.0″ | ±0.005″ |
| Stainless Steel | 0.75″ | ±0.005″ |
| Aluminum | 0.50″ | ±0.005″ |
| Brass | 0.375″ | ±0.005″ |
| Copper | 0.25″ | ±0.008″ |
Design Tips for Laser Cutting
Kerf Width
The laser beam removes a thin strip of material (the kerf). Typical kerf: 0.006–0.015″ depending on material and thickness. The machine compensates automatically, but know that internal corners will have a radius equal to half the kerf width.
Minimum Feature Size
- Minimum hole diameter: ≥ material thickness (0.030″ minimum)
- Minimum slot width: ≥ material thickness
- Minimum web (material between features): ≥ material thickness
- Minimum tab/finger: 2× material thickness wide
Heat-Affected Zone (HAZ)
Laser cutting heats the edge. The HAZ is typically 0.004–0.020″ deep depending on material and thickness. For most applications, this is irrelevant. For hardened materials or precision fits, plan to remove the HAZ by machining.
Edge Quality
- Nitrogen assist: Clean, oxide-free edge. Best for stainless and aluminum. Ready to weld.
- Oxygen assist: Creates a thin oxide layer on steel edges. Faster cutting. Fine for painting/powder coating. Not ideal for welding (remove oxide first).
Nesting
Laser-cut parts are “nested” — arranged on the sheet like puzzle pieces to minimize waste. Good nesting can reduce material cost by 10–20%. If you’re ordering multiple part numbers, ask the shop to nest them on the same sheet.
When Laser Cutting Isn’t the Answer
- Material > 1″: Consider plasma or waterjet
- Non-metals (wood, stone, glass): Use waterjet or CO₂ laser
- Very high volume (>50,000 identical parts): Stamping is cheaper per part
- 3D features: Laser cuts 2D profiles. For 3D, you need 5-axis laser cutting (rare) or a different process.
Need laser-cut parts? Send us your DXF or drawing — we’ll quote it within a day.